Functionality of conventional Digital Still Cameras (DSC) and conventional camcorders are converging. The DSCs implement sensors (i.e., CCD or CMOS) with at least 4 to 5 million pixels. A video signal in a typical camcorder is acquired at 30 to 60 frames per seconds with a resolution varying from 720×480 (i.e., standard definition) to 1920×1080 (i.e., high definition) viewable pixels. The availability of sensors that can combine both a high pixel number to accommodate DSCs and a transfer rate to accommodate video allows an introduction of a new digital zoom function that is quite different from the current digital zoom function used in conventional cameras and camcorders.
A conventional digital zoom operation, also called “interpolated” zoom, is achieved by calculating an up-conversion of a window in existing image data to generate an enlarged version. Interpolated zoom is achieved by cropping a window in a standard resolution picture and enlarging the window by interpolation. The resulting image has a progressively decreasing resolution as the cropping factor increases. The decreasing spatial resolution has created a feeling among users that digital zoom is a technique inferior to a true optical zoom.